Feed apparatus for corrugated box blanks

ABSTRACT

Apparatus for feeding in synchronous fashion box blanks to a box blank processing apparatus, to assure that the blanks are supplied in positive timed relation notwithstanding distortion of the box blanks. The apparatus includes speed change means to prevent interference between projections on the feeding apparatus and the trailing edges of the box blanks during transfer of the blanks to the processing apparatus.

United States Patent Inventor William F. Pulda Edison, NJ.

Appl. No. 9,285

Filed Feb. 6, 1970 Patented Dec. 14, 1971 Assignee Universal Corrugated Box Machinery Corporation Cranford, NJ.

FEED APPARATUS FOR CORRUGATED BOX BLANKS 9 Claims, 5 Drawing Figs.

US. Cl 271/45, 271/69 Int. Cl B65h 5/16 Field of Search .I 271/45, 46,

Primary Examiner-Joseph Wegbreit Assistant ExaminerBruce H. Stoner, .lr. AImmeyArthur B. Colvin ABSTRACT: Apparatus for feeding in synchronous fashion box blanks to a box blank processing apparatus, to assure that the blanks are supplied in positive timed relation notwithstanding distortion of the box blanks. The apparatus includes speed change means to prevent interference between projections on the feeding apparatus and the trailing edges of the box blanks during transfer of the blanks to the processing apparatus.

PATENTEU mam l9" 315273 1 0 sum 1 or 4 ML/AM F Pul. 04

FEED APPARATUS FOR CORRUGATED BOX BLANKS BACKGROUND OF THE INVENTION 1. Field of the Invention This invention is in the field of box-fabricating apparatus and relates more particularly to a feed mechanism for advancing box blanks, and particularly corrugated board box blanks to a subsequent processing apparatus in precise timed relation to the operation of the processing apparatus.

2. The Prior Art The feed of box blanks fabricated of corrugated board in volves considerable problems which are essentially unique to the processing of this material.

As is well known, corrugated board comprises a plurality of plies, generally three, which are glued together. A central ply is arranged in a sinuous path, to lend considerable thickness and stiffness to the board without materially increasing its weight.

The exposed outer plies are generally fabricated of different materials in accordance with their intended end function. Thus, the ply which is to form the outer surface of the folded box will normally be made of a paper material which is denser than the inner ply and hence more highly resistant to abrasion and susceptible of receiving an overprint without blotting.

It should further be appreciated that the box blanks or the stock material for forming the blanks may be fabricated under a given set of temperature and humidity conditions, stored for a period of time, and subsequently processed in an environment having a second and different set of ambient temperature and humidity factors.

Thus, the blanks will often become distorted to a warped, curled or bowed configuration, resulting from factors such as, by way of example, differential shrinkage or stretching of the inner or outer plies because of unequal water absorption or uneven glue application, unequal reaction of the plies to a second set of atmospheric conditions, etc.

It will be readily recognized that, as a result of the distortion of the box blanks, it is particularly difficult to feed the same with a high degree of accuracy, as contrasted for instance with a precisely planar blank. As a result of this difficulty, a high percentage of corrugated box blanks are misformed by subsequent processing steps, such as, for example, folding and scoring.

The standard means of combatting the problems which inhere in feeding corrugated box blanks has been the utilization of production lines which operate at relatively slow speeds, to permit additional time for manual or other alignment of the blanks. Obviously, reduced production speed and increased supervisory labor are economically undesirable measures.

SUMMARY OF THE INVENTION The invention may be summarized as relating to a feed apparatus for box blanks, and particularly corrugated box blanks, which feed apparatus is capable of operating at high speeds and synchronously advancing even warped or distorted box blanks to a processing apparatus, such as a folding machine.

The feed apparatus includes a conveyor having a plurality of article advance blades or projections extending therefrom, the conveyor being of the endless belt or chain type. The blanks are received on the upper flight. The projections extend normal to the conveyor surface, preferably for a considerable distance to assure that the lead edge of a conveyor blade will engage against a trailing end of a box blank, notwithstanding distortion or warping of the box blank which might result in the trailing edge of the blank being spaced a considerable distance from the surface of the conveyor.

The projections or blades include forwardly directed shoulders overlying the blank, assuring that the rear faces thereof may not shift too far from the surface of the conveyor and pass over the feed blades.

The blanks are advanced by the projections to a processing apparatus which operates in synchronism with the conveyor.

The requirement that the projections extend a considerable distance from the surface of the conveyor, and the provision the forwardly directed shoulders aforesaid, give rise to a further problem, notably the prevention of interference between the projections and the trailing edge of the box blank as the projections shift from the upper or feed flight of the conveyor, through a transition zone, and to the lower flight of the conveyor.

An important feature of the invention lies in the provision of a novel timing mechanism which prevents interference of the type aforesaid.

The timing mechanism may be powered by a power takeoff from the processing device. The timing mechanism includes novel means for decelerating the conveyor at the critical stage during which the projections are shifted from the upper to the lower flight, the box blanks being removed from the conveyor at a constant speed. The timing mechanism accelerates the conveyor after the trailing edge of the blank has been shifted to a position sufficiently downstream to avoid the possibility of interference between the projections and the blank.

Accordingly, it is an object of the invention to provide a novel feed mechanism for box blanks and particularly corrugated box blanks wherein the blanks are rapidly and accurately fed to a subsequent processing mechanism, notwithstanding distortion or warping of the blank.

A further object of the invention is the provision of a device of the type described and including feed projections having shoulders or hooks which are forwardly directed and which assure that the blanks are maintained in a desired aligned position.

A further object of the invention is the provision of a device of the class described which includes a novel timing device for decelerating and accelerating the box blank feed conveyor, respectively, as the box advance projections extend from the upper flight, into a transition zone and, after the projections have passed at least partially through the transition zone.

In the accompanying drawings in which is shown one of various possible embodiments of the several features of the invention:

FIG. 1 is a perspective view of a feed apparatus of the type described, illustrating in addition the introductory component of a subsequent processing device, such as a folder;

FIG. 2 is an enlarged vertical section taken on the line 2-2 of FIG. 1;

FIG. 3 is a section taken on line 33 of FIG. 2;

FIG. 4 is a magnified sectional view taken on line 4-4 of FIG. I; and

FIG. 5 is a view similar to FIG. 4 showing the position of the parts at a further advanced position in the feed cycle.

In accordance with the invention, 10 is a feed apparatus in the nature of a conveyor, which functions to advance box blanks B deposited on the upper flight of the conveyor to the initial stage 11 or loading zone of a processing apparatus 12. It will be appreciated that the processing apparatus 12 is calculated to perform a known series of operations on the box blanks, such as folding and gluing. Details of the processing apparatus, accordingly, will not be discussed except to point out that it is essential that blanks B be received on the processing apparatus I2 in a precise, timed relation such that the trailing edges of the blanks are positioned to be engaged by advancing blades 13 of the processing apparatus 12. It will be appreciated by way of illustration that the blades 13 are carried on a cross bar I4 extending between a spaced pair of chains 15, 16, mounted on sprockets 17, 18, respectively.

The boxes B are delivered onto the side supports 19, 20, the support surfaces of which are mounted in coplanar alignment with the upper edge of central T support 21.

It will be understood that the blades 13 engage behind the trailing edges of the blanks and advance the same along to further processing steps. It is imperative, for economical production, that the trailing edges of the blanks be so positioned as to be picked up by the blades 13 without delay or lost motion.

It is the function of the conveyor 10, which is the subject of the present invention, to deliver the blanks which may be manually placed thereon one by one, in timed sequence, to achieve the most efficient possible operation of the processing apparatus.

The feed apparatus is powered by a chain drive 22 which may be directly connected with the feed apparatus of the processing device to achieve a timed interrelation of these parts. There is shown at 23 a speed change mechanism which forms a part of the feed apparatus 10.

Twenty-four is an input drive gear for powering the conveyor portion 25 of the feed apparatus 10. The conveyor includes a plurality of support tables 26, 26, 26, which are spaced apart to define therebetween a pair of upwardly open slots 27, 28. A pair of chain support shafts 29, 30 are journaled on an appropriate frame structure (not shown). The shafts 29, 30 have fixed thereto drive sprockets 31, 32, respectively, four in number, being shown for each shaft.

As will be evident from an inspection of FIG. 1, a drive sprocket 31 of shaft 29 is aligned with each of the slots 27 and 28 between the support tables 26, and another sprocket 31 is disposed at the lateral edges 34, 35 of the two outermost support tables. Drive sprockets 32 are comparably aligned on the shaft 30.

A chain flight 33 is mounted on each pair of opposed sprockets 31, 32, there thus being four chain flights, two of which flights are disposed at the outermost edges 34, 35 of the tables 26, with a further chain flight 33 being arrayed within each of the slots 27 and 28. The uppermost surfaces of the chain flights 33 are disposed slightly below the level of the tables 26.

The chain flights 33 carry transversely extending box feed blades or bars 36 (three being disclosed in the illustrated embodiment). It will be appreciated that the blades or bars 36 are separated by equal increments of the chain 33, the bars being preferably secured to the chains by a removable connector mechanism (not shown) so as to permit the bars to be connected at any position along the length of the chain, to adapt the apparatus for box blanks of differing lengths.

As best seen in FIGS. 4 and 5, a series of four connector links 37 are fixed in aligned transverse relation to appropriate increments of each chain, the links 37 being individually attached to an extending angle iron 38. Transversely extending pusher blade 39 is bolted, as by bolts 40, to the angle irons. Each blade 39 includes a forwardly extending holddown shoulder or ledge 41.

As best seen in FIG. 4, the purpose of the holddown ledge 41 is to assure that the rear or trailing edges Te of the box blanks B are maintained against the feed surface of the blades and cannot pass over the top of the blades.

The box blank B depicted in FIG. 4 is shown to be warped or distorted in such manner that the rear edge Te of the blank is spaced upwardly from the table. This condition frequently results, as previously explained, from the tendency of the lower ply which normally will form the outer face of the finished box to shrink less than the upper and less dense ply which will form the interior of the box. Under such circumstances, the overhand ledge 41 provides a high degree of control, to assure accurate feed, notwithstanding the configuration assumed by the blanks B.

Thus, when a box blank is placed on the table, the worker need merely press down. the trailing edge Te so that it will be beneath the ledge 41 when the feed surface of the blade engages the trailing edge Te.

The conveyor chains 33 are driven through the medium of the speed change mechanism 23 by drive of input chain 22. it has been determined that if the chains 33 were advanced at a constant rate, and pusher blades employing the hooklike projections 41 were employed with such conveyor, interference would develop in the area where the blades pass form a purely horizontal direction of advance through the downward or transition zone extending between the upper and the lower flights of the chains 33. Since the box blanks have a certain drag or frictional engagement with the tables, the trailing edges Te of the blank always bear against the lead surfaces of the blades. As the blades shift from a strictly horizontal advance path through a path which includes both horizontal and vertical components of movement, the trailing edges or ends of the blanks would be caught under the portions 41. As a result of the engagement of the portion 41 against the upper surface of the blank, a series of deleterious effects is observed, including (depending on the warped configuration of the blank) creasing, bending or even tearing of the blanks.

At best, such interference with the blanks will result in formation of a defective box, and in the event of severe damage may cause a jamming of the mechanism.

It has been discovered that the undesirable jamming and other disadvantageous effects may be obviated by providing a conveyor which advances the blanks at a first speed during the linear movement of the blades 39 toward the processing apparatus. As the blades begin a combined horizontal and vertical movement, the conveyor must be decelerated, permitting succeeding feed apparatus to clear the trailing edges of the box blanks from their position beneath the extension 41 of the blades, i.e., to the position shown in FIG. 5. At this point, the conveyor chains 33 may again be accelerated, to counteract the decelerating effects previously set forth. In this manner the average speed of advance of the box blanks may be precisely determined and synchronized with the succeeding mechanisms.

The speed change mechanism is particularly advantageous where the pusher blades include portions (such as the portions 41) which overlie the upper surface of the box blanks, although such change mechanism may also be advantageously employed in apparatuses using nonoverhanging pusher blades.

Turning now to the details of the speed change mechanism, and with particular references to FIGS. 1, 2 and 3, gear 42 is mounted on shaft 43, which shaft also carries drive sprocket 44, meshed with input drive chain 22. Gear 42 meshes with gear 45, fixed to main shaft 46. Speed changer output gear 47 is mounted on the shaft 46 in a manner permitting relative rotation of the gear 47 with respect to the shaft. A drive hub 48 is also rotatably mounted on the main shaft 46 adjacent the output gear 47. The gear 47 is preferably recessed at 49, the hub 48 including a lateral extension portion 50 which nests within the recess 49. A cross pin 51 links the hub 48 to the output gear 47, preventing relative rotation of these parts.

Fifty-two represents a stationary portion of the support frame for the speed change apparatus, the shaft 46 being journaled for rotation with bearing aperture 53 formed in the frame. A drive arm 54 is keyed to the main shaft 46, the arm 54 including at its end 55 spaced from the shaft, a pair of legs 56, 57. A pin 58 is fixedly mounted within cross apertures fonned in the legs 56, 57.

The hub 48 is provided, in radial spaced relation to the axis of shaft 46, with a cross bore 59 pivotally supporting a trunnion or bridge pin 60, A pair of torque transmitting levers 61, 62 are fixedly mounted to opposite ends of the trunnion 60, such that the pin and levers may pivot as a unit within the cross bore 59 about a pivot axis paralleling the axis of the shaft 46.

The radial inner end 63 of the lever 61 is forked, defining legs 64, 65 which loosely straddle the pin 58 mounted between the legs 56, 57 of the drive lever 54. It will be appreciated that the legs 64, 65 lie within the space between the legs 56, 57 of the drive lever, thus permitting both a pivotal and a radial shifting movement between the respective levers 61 and 64. The connection between the outer end 55 of the lever 54 and the inner end 63 of the lever 61 is in the nature of a clevis connection. I

Although the hub 48 and output gear 47 are freely rotatable about shaft 46, they are contained against axial shifting movement along the shaft. For this purpose spacer collar 66, engaging against the gear 47, and collar 67, engaging against a bearing ring forming a part of the hub 48, are locked to the shaft 46, to maintain the desired juxtaposed position of the noted parts.

The lever 62 which is fixed to pin 60 carries at its inner end a roller or follower assembly 68. A roller 69 is rotatably mounted on carrier pin 70, an end 71 of which is threaded to receive locknut 72. The carrier pin 70 extends through a bore 73 formed at the end of the lever remote from the pin 60.

The roller 69 is positioned within a cam track 74 formed on a stationary cam assembly 75, which is mounted on a fixed portion of the frame (not shown). The shaft 46 is rotatably journaled within bearing components defined in the cam assembly 75.

The cam track 74 is fonned within a disclike cam insert 76, having a generally circular end flange 77 projecting laterally beyond the edges of the disc. The cam disc insert 76 is locked against movement relative to the frame portion of the cam assembly by clamp brackets 78, which are internally threaded to receive machine screw 79 extending through a fixed end wall 80 of the cam assembly 75. A plurality of connectors, such as the clamp bracket 78, engage against and lock the insert 76 in a selected position, adjustment of the insert relative to the fixed portion 80 being preferably permitted by a releasing and resetting of the machine screws 79.

The configuration of the cam track 74 which embraces the follower or roller 69 is such as to cause the pin 60 to pivot within the bearing 59 about an axis which parallels the axis of the shaft 46.

The cam track 74 includes a first section X (see FIG. 3) wherein the cam follower 69 can neither approach nor move outwardly with respect to the axis of the shaft 46. When the roller 69 traverses the cam section X, it will be appreciated that no pivotal movement is imparted to the pin 60. Accordingly, as the roller traverses this cam section, the hub 48 and hence, the output gear 47 cannot rotate relative to the shaft 46 and the angular speed of these parts will perforce be the same, i.e., the speed ofshaft 46.

Section Y of the cam track may be called the retar section of the track since, as the follower roller traverses this section, an anticlockwise movement is imparted to the pin 60. As a result of the anticlockwise movement of the pin, the hub 48 is caused to move in a clockwise direction relative to the shaft 46 i.e., in a direction opposite to the direction of rotation of the shaft 46.

It will thus be appreciated that this counter rotation of the hub has a subtractive effect as respects the angular speed of the hub and, as a result, as the roller is translated across the section Y, the annular speed of the hub will be less than the angular speed of the shaft 46. Since the hub is connected by pin 5! to the output gear 47, it will be understood that the drive gear 47 is decelerating or more aptly, is moving more slowly than shaft 46 during the time that the roller 69 is scanning the cam section Y.

As the roller traverses the cam section Z, an opposite rotation of the pin 60 is affected since the roller is moving outwardly as it traverses this section of the track. Accordingly, the hub is again relatively rotated with respect to shaft 46, in this instance in a direction to apply a cumulative effect resulting in the rotation of the hub 48 and output gear 47 at a speed which exceeds the angular speed of shaft 46.

From the foregoing it will be observed that with each rotation of the shaft 46, the conveyor chains 33 which are driven from shaft 30, carrying gear 24, meshed with speed change output gear 47, are decelerated and accelerated, the precise timing of deceleration and acceleration being readily adjustable by a simple adjustment of the cam insert 77 within the cam housing 80.

While, for purposes of clarity, the cam of the illustrated embodiment depicts a single deceleration and a single acceleration during each cycle of rotation, it will be readily recognized that multiple cylindrical decelerations and accelerations may be obtained simply by substituting for the illustrated cam insert, a cam insert having a plurality of dips and peaks.

Similarly, the length and angularity of the cam segments X, Y and Z will determine the duration and degree of acceleration and deceleration.

The box blanks emerging from the trailing end or discharge station D of the conveyor 25 are, in the illustrated embodiment, picked up between a pair of counterrotating nip rollers 81, 82 which are driven normally at a constant speed which is at least equal to the average speed of the conveyor chains 33. Preferably, a pair of inclined guide plates 83, 84 are interposed between the discharge station D and the rollers 81, 82.

The guide plates converge toward a slot disposed in substantial alignment with the nip of the rollers 81, 82, the spread apart, trailing ends of the plates operating to gather and centralize the lead edge of a box blank, to facilitate its optimal positioning with respect to the rollers.

The operation of the drive blades 13 of the processing mechanism 12 is, of course, in timed coordination with the remaining portions of the apparatus so that the blades will engage directly behind the trailing edges of box blanks B emerging from the rollers 81,82.

From the foregoing it will be appreciated that there is provided by the present invention a feed mechanism of particular applicability to the processing of corrugated cardboard or like readily warped sheet material, which material, by reason of its warping propensities, may desirably be fed by conveyor blades or projections which incorporate overlapping hooks or hold down shoulders. The novel speed change mechanism permits the use of such hooked feed projections without the possibility of interference between the projections and the trailing edges of box blanks or the like as the projections are shifted from a horizontal locus to a combined horizontal and vertical locus, i.e., as they shift from the upper flight to the transition between the upper and lower chain flights.

The speed change mechanism is in all respects automatic, providing during each rotating cycle a precisely timed and coordinated decelerating and accelerating factor, thus assuring that the speed of the conveyor is maintained within a precisely defined range.

Although the conveyor has been illustrated as employing chain drives for the pusher blades, for instance, it will be readily understood that other drive mechanisms, such as timed belt drives, may be advantageously employed.

The invention is therefore to be broadly construed within the scope of the appended claims.

Having thus described my invention, what I claim as new and desire to secure by Letters Patent of the United States is:

1. in a box-fabricating apparatus or the like including a processing device for effecting a forming operation on box blanks, means for feeding blanks in timed sequence to said processing device comprising an input drive synchronized with and powered by said processing device, input feed con veyor means for serially advancing said blanks to said processing device, said conveyor means being of the endless band-type and including an upper flight, a lower flight and a transition section between said flights defining a discharge station, a pickup station for said processing device adjacent said discharge station for receiving said discharged blanks, a plurality of blank drive projection means extending perpendicularly from said conveyor for engaging behind and advancing said blanks along said upper flight of said conveyor means, and speed change means interposed between said input drive and said conveyor means for automatically decelerating said conveyor as said drive projection means move from said upper flight through said transition section, thereby to prevent interference between said projection means and the trailing ends of said blanks at said section.

2. A device in accordance with claim 1 wherein said pickup station includes feed means for advancing, at a constant speed, blanks delivered to said station.

3. A device in accordance with claim 1 wherein said speed change means automatically accelerates said conveyor means when said drive projections are shifted past said discharge station.

4. A device in accordance with claim 1 wherein said blank drive projections include inner end portions fixed to said conveyor, and holddown shoulder means at their distal ends extending in the direction of movement of said conveyor and spaced therefrom to limit outward movement of the trailing ends of said blanks from said conveyor.

5. A device in accordance with claim 1 wherein said speed change means comprises a main shaft driven by said input drive, an output drive mounted for rotation relative to said shaft, said output drive being in driving connection with said conveyor means, a speed change hub mounted for rotation on said main shaft in driving connection with said output drive, power transfer means coupled to said drive shaft, connector means coupling said power transfer means to said hub while permitting limited relative rotative movement between said hub and transfer means about the axis of rotation of said main shaft, and cam means operatively associated with said connector means for relatively rotating said hub and transfer means between retarded and advanced relative rotated positions during each rotation of said main shaft.

6. The device of claim 1 wherein the speed change means comprises a main shaft driven by said input drive, an output drive on said main shaft for rotation relative thereto, said output drive being in driving connection with said conveyor means, a speed change hub mounted for rotation on said main shaft in driving connection with said output drive, a power transfer member coupled to said drive shaft and extending radially therefrom, bearing means on said transfer member in radially spaced relation to and in parallel alignment with the axis of said main shaft, a cross shaft carried by said hub and pivotal about an axis parallel with said main shaft, a first lever arm having one end fixed to said cross shaft and having its other end pivotally connected to said bearing means of said transfer means, a second lever arm fixed to said cross shaft, and cam means operatively associated with said second lever arm to shift said arm and pivot said cross shaft about said parallel axis, thus to relatively rotate said hub and said main shaft.

77 A device in accordance with claim 6 wherein said second lever arm includes a follower roller and said cam means comprises a stationary cam track engaging said follower roller, said cross shaft being rotated in said hub in accordance with the configuration of said cam track.

8. A device in accordance with claim 6 wherein the connection between said bearing means of said transfer member and said other end of said first lever arm permits relative radial movement of said bearing means and arm.

9. A device in accordance with claim 6 wherein the connection between said other end of said first lever arm and said bearing means is defined by a clevis member and a pin member one said member being carried by the transfer member and the other said member being carried by first lever arm.

II It i i i 

1. In a box-fabricating apparatus or the like including a processing device for effecting a forming operation on box blanks, means for feeding blanks in timed sequence to said processing device comprising an input drive synchronized with and powered by said processing device, input feed conveyor means for serially advancing said blanks to said processing device, said conveyor means being of the endless band-type and including an upper flight, a lower flight and a transition section between said flights defining a discharge station, a pickup station for said processing device adjacent said discharge station for receiving said discharged blanks, a plurality of blank drive projection means extending perpendicularly from said conveyor for engaging behind and advancing said blanks along said upper flight of said conveyor means, and speed change means interposed between said input drive and said conveyor means for automatically decelerating said conveyor as said drive projection means move from said upper flight through said transition section, thereby to prevent interference between said projection means and the trailing ends of said blanks at said section.
 2. A device in accordance with claim 1 wherein said pickup station includes feed means for advancing, at a constant speed, blanks delivered to said station.
 3. A device in accordance with claim 1 wherein said speed change means automatically accelerates said conveyor means when said drive projections are shifted past said discharge station.
 4. A device in accordance with claim 1 wherein said blank drive projections include inner end portions fixed to said conveyor, and holddown shoulder means at their distal ends extending in the direction of movement of said conveyor and spaced therefrom to limit outward movement of the trailing ends of said blanks from said conveyor.
 5. A device in accordance with claim 1 wherein said speed change means comprises a main shaft driven by said input drive, an output drive mounted for rotation relative to said shaft, said output drive being in driving connection with said conveyor means, a speed change hub mounted for rotation on said main shaft in driving connection with said output drive, power transfer means coupled to said drive shaft, connector means coupling said power transfer means to said hub while permitting limited relative rotative movement between said hub and transfer means about the axis of rotation of said main shaft, and cam means operatively associated with said connector means for relatively rotating said hub and transfer means between retarded and advanced relative rotated positions during each rotation of said main shaft.
 6. The device of claim 1 wherein the speed change means comprises a main shaft driven by said input drive, an output drive on said main shaft for rotation relative thereto, said output drive being in driving connection with said conveyor means, a speed change hub mounted for rotation on said main shaft in driving connection with said output drive, a power transfer member coupled to said drive shaft and extending radially therefrom, bearing means on said transfer member in radially spaced relation to and in parallel alignment with the axis of said main shaft, a cross shaft carried by said hub and pivotal about an axis parallel with said main shaft, a first lever arm having one end fixed to said cross shaft and having its other end pivotally connected to said bearing means of said transfer means, a second lever arm fixed to said cross shaft, and cam means operatively associated with said second lever arm to shift said arm and pivot said cross shaft about said parallel axis, thus to relatively rotate said hub and said main shaft.
 7. A device in accordance with claim 6 wherein said second lever arm includes a follower roller and said cam means comprises a stationary cam track engaging said follower roller, said cross shaft being rotated in said hub in accordance with the configuration of said cam track.
 8. A devIce in accordance with claim 6 wherein the connection between said bearing means of said transfer member and said other end of said first lever arm permits relative radial movement of said bearing means and arm.
 9. A device in accordance with claim 6 wherein the connection between said other end of said first lever arm and said bearing means is defined by a clevis member and a pin member one said member being carried by the transfer member and the other said member being carried by said first lever arm. 